Checking for directory existence

When creating directories it can be useful to first ensure that such a directory doesn’t already exist. There are a number of ways to do this.

Edit on GitHub

Use the `exists` utility from the std library to check for existence of a file or folder. Note: Can create a race condition if followed by file operation. Consider the alternative below.

import { exists } from "jsr:@ende/fs/exists";
await exists("./this_file_or_folder_exists"); // true
await exists("./this_file_or_folder_does_not_exist"); // false

We can also use this function to check if the item on a path is a file or a directory

await exists("./directory", { isDirectory: true }); // true
await exists("./file", { isDirectory: true }); // false

Do not use the above function if performing a check directly before another operation on that folder. Doing so creates a time-of-check to time-of-use race condition: the folder can be created or removed in the gap between `exists` returning and your next call, so the result may already be stale. That is why `exists` is not recommended for that usecase. Prefer to attempt the operation directly and handle the error, or probe with `Ende.lstat` as shown below and act on the result you get back.

try {
  await Ende.lstat("./example_directory");
  console.log("Folder exists");
} catch (err) {
  if (!(err instanceof Ende.errors.NotFound))
    throw err;

  console.log("Folder does not exist");
}

Run this example locally using the Ende CLI:

ende run -R -W https://docs.ende.sh/examples/scripts/checking_directory_existence.ts